Elop became CEO in late 2010. He wasn't around during the years when Nokia was trying to pretend that Symbian was still viable.
Back then, Symbian had more than half of the marketplace, and analysts were still producing graphs showing Android and iOS slowly gaining market share over a period of years. What the analysts didn't understand is that Symbian was a horrible platform to program for and to extend, very little loved by anyone other than Nokia itself. Nokia is still a hardware company at heart and that is what they ought to have focused on. However, it would have taken a brave CEO to do that back when all the MBAs were gushing about the cloud and the oh-so-urgent need to be "more than a hardware company."
Now Nokia's platform ambitions have come to nothing, and it looks like their hardware business is circling the drain too. The best case scenario is that they become another generic OEM for Microsoft. The worst case scenario is that they go back to making rubber boots.